Originally posted by FabianFnas
This is an interesting discussion, disregarded if I'm right or if i'm wrong.
I think that you cannot compare the nuclear fusion reaction in a H-bomb, which is higly chatotic and generate nothing more than heat in a very short instant of time, and a highly controlled reaction in a fusion plant to generate electric power.
The most interesting fusion r ...[text shortened]... is debateable thereafter is about the efficiency of the process to generate electrical power.
I havn't checked your formula, but assuming it is correct (I dont know off the top of my head), lets put some numbers in it to get an estimate.
Deuterium is 1 proton and 1 neutron, so has a mass of 2a.m.u.
Tritium is 1 proton and 2 neutrons so has a mass of 3a.m.u.
The equation has one deuterium and one tritium joining together. So for each reaction we require 5a.m.u of matter. (a.m.u is atomic mass units by the way. 1 a.m.u = 1.6*10^-27kg).
So for each reaction we need 5*1.6*10^-27 = 8*10^-27kg of fuel.
So with one kg of fuel we can have 1/(8*10^-27) = 1.25*10^26
Each reaction puts out 5.2*10^-13J, so from one kg of fuel we get:
5.2*10^-13 * 1.25*10^26 = 6.5*10^13J
So now lets convert this into kilowatthours (kWh) as requested.
1 kWh is 1000J of energy every second for an hour.
In an hour there are 60*60 = 3600 seconds.
So for 1kW/h we need 1000*3600 = 3.6*10^6J
So from our 1kg of fuel we get 6.5*10^13 / 3.6*10^6 = 18.1*10^6kWh!
Perhaps not enough to get a light bulb running for millions of years (works out at about 20,000 years for a 100W bulb), but still a vast amount of energy! AND all from just 1kg of fusion fuel!
Also, to address the start of your post. we can compare neclear fusion reaction in a H-bomb with that in a reactor. It is the exact same process, but the reactor has it happening a small amount at once over a long time whereas the bomb does it all at once in a chain reaction. The energy output is the same as long as the same amount of material has been fused. Also, you keep talking about "nothing more then heat" is generated. This is the same as in a coal powerplant, you burn the fuel to get HEAT. The heat is then transferred into electricity, usually by using pressurised gas in a turbine. This is what happens in a fusion plant also, we dont get electricity straight from the reaction.
However, it turns out that the higher the temperature of a reactor the more efficient the heat transfer stage of the process is. Fusion reactors have temperatures of literally 100million K, so are far FAR hotter then normal power plants. So I imagine that they are more efficient. But as you correctly point out they will not be anywhere near 100%!
I hope this was helpful 🙂 You may want to check my calculations because I was in a rush hehe.